期刊名称：Journal of Nutritional Science and Vitaminology
印刷版ISSN：0301-4800
电子版ISSN：1881-7742
出版年度：2000
卷号：46
期号：1
页码：23-29
DOI：10.3177/jnsv.46.23
出版社：Center for Academic Publications Japan
摘要：The insoluble 'high-molecular-weight' fraction (HMF) centrifugally separable after digestion of soy protein isolate with a microbial protease of the exo-type, of which about a quarter is regarded as an indigestible 'resistant protein, ' was examined for its pre-ventive effect against colonic tumorigenesis in a model system with male F-344 rats. The rats were intraperitoneally injected with azoxymethane (15 mg/kg BW) once a week for 3 wk and were fed a 206% .HMF diet (+0.4% DL-Met) or 14.7% casein diet (+03%, DL-Met) supplemented with 0.2% sodium deoxycholate (DCA) or without supplementation. Twelve wk later, 5 rats of each group were inspected for formation of tumors but no tumors were visible to the naked eye. The DCA-fed casein group was conspicuous for a low count of aber-rant crypt foci. At 39 wk, 6 rats of the DCA-fed casein group ( n =10) and 3 rats of the DCA-fed HMF group ( n =9) had a total of 18 tumors with a major axis of 4.0±0.4mm and 3 tu-mors with an axis of 2.0±0.1 mm, respectively, in contrast to only a single tumor for the DCA-unfed casein group (nil for the DCA-unfed HMF group). The difference in tumor num-ber and size was considered significant between these DCA-fed casein and HMF groups; that is to say, HMF feeding retarded tumor development despite the frequent occurrence of pre-neoplastic lesions. In addition, fecal bile acid excretion was much more elevated by HMF feeding than by casein feeding. It can be assumed from these observations that the antitu-morigenicity of HMF is due to the inhibitory effect of soybean resistant proteins on reabsorp-tion as well as the mucosal contact of bile acids in the intestine.
